This invention relates to an inflatable storm window that can be packaged in a rolled up or folded state. On partial inflation, the window will balloon out to the desired rectangular shape. At this point it can be fitted into the window opening, covering the existing sash and forming an airtight barrier with the window frame. The inflatable window is made from a flexible material which readily adjusts in size to the variations in tolerances experienced in the building trade. For example, applicant has found that there will be at least a half inch of size variation in the horizontal and vertical wall opening dimensions associated with a window having a nominal 3 foot by 3 foot frame size.
A search of the related art reveals that in the U.S. Pat. No. 3,918,512 to Kuneman, there is disclosed an inflatable window panel. Mr. Kuneman eliminates air leakage through an inner window, outer storm window combination by placing an inflatable plastic bag between the two windows. Enough pressure is added to the bag to make it firmly contact the frame periphery between sashes. Nally in U.S. Pat. No. 3,911,630 discloses a storm window comprising a rigid self supporting transparent sheet or pane having a second flexible transparent sheet overlying the first. The flexible sheet is peripherally attached to the first at the sash or frame, thus providing an inflatable dead airspace between the two sheets for preventing heat loss through the window opening. Lux, et al., in U.S. Pat. No. 2,825,941 discloses an inflatable closure sealer, formed somewhat as a tube, that serves as a sealing strip between a rigid window pane and the surrounding window frame.
None of the references cited above disclose the features of my invention. I first observed that a ring shaped tubular device, for example, a bicycle inner tube would expand in diameter on being inflated. Expansion of the tube is such that both the inner and outer diameter increases. Thereafter, I discovered that a transparent flexible sheet fused to the innermost circumference of a bicycle innertube will be stretched taut on inflation of the tube. Very few windows are round. However, I next discovered that a rectangular tubular structure having a sheet of transparent flexible film fuzed to its innermost edge would expand to fill a rectangular opening. This discovery makes it possible to inexpensively fabricate a storm window sash which forms a barrier that virtually eliminates the air leakage through and around a conventional window sash glazed with glass. The inflatable window also cuts convective heat losses by a large amount.